Lee de forest



PATENTED JAN. 12, 1904'.

LIDE FOREST.

WIRELESS TELEGRAPH RANGE FINDER.

APPLICATION FILED JUNE 17. 1903.

N0 MODEL.

FigQ- WITNESSES:

INVENTOH 2;; A THNEY for WiFiELn SPECIIFECATZON forming part of Letters "fatent No. 74931355, dated Janum'y 12, 19 04.

Application tilsd June 1'7, 1903. Serial No. 161,890. (Ho model.)

To {Ii/"Z when? it 'rrm-y norm/Wu:

nown that l imn or: Fl inicsi". a

'tizen of L teil Stains. anal a resillcnliol' lho citv.

on :il 5 -Icw Yorln lizivrinx oil lollowin 2). s) ilicnricn.

M invention rclalcs l an improvement in wirelcss-tclcgrnph receiving (lcviccs whorchy an indication of th distance to tho transmitiing psrzitus run; he hall.

The scope of my invention may h incil h the ypeci nnncxcil.

The :l nwin nnncxol hcreunto show my invention cnmo iecl in simple forms of nppzi rains, such as are now preferred by me.

Figures l and 2 each show a receiving apparatus leinhcilying in inv ntion, huc slightly differing from czicli other.

With many forms of wircloss-tolegraph rccciving apparatus the inte sit vor' lhe action of the 210ll21ll,\' ci'vcil warns upon the indicatingniochzin hears :i ilcilnitc rclntion to the distance oi the snitiou from which t-liov werev ml. ii llGlTlQ' g sumcrl that the. intensity n constant. ll w ,l

" moans: ho p'oviilcil for th intensity of tho ,Pnsity of rzulirc 'cpzirzition of liic trimsionsinn v he t lcast i have f0iilil c 'lc'tcrlicizrion and claims hereunto illilli'HXl plc nu".

' olll 'll'(.'lllli()l lll jlllll1\lll lillul'eil hyill fi -rri-civcll wnvcs until ilic cll'ccri o ll rccchul impulses is ncntrzilizoil or llili'lll down in suhs'tnnliallv zcro. ui l csislnnrm l iiugin crlihlc l inricincnhv which hour a: known riiiio to tho distance powcr of :1 stauulziril tr: "isiniilcr. the those incrcnicnts having" lim-n previously cnrci'ullv ilctQl'llllllUll lor lii'i'crcnt ilistzinccs null for Lrnr nii(ting-stniion olilil'l'crcnt power. With tluv information "l dl'illl i1 is possihlc to quickly approx: i. l'hv il tziui-c from ii flown sl::- 3 lion whcn llu powcr iiicrcol' is l =1 pic minuis of llli (ll nvn in l i; l zznil "J. in rlpil' r-nls llh" collcc" E tlliilii 5 is pine-oil in s now. shown as coils nrhcostnt; S, ahlc switch (:2

thcn1ovihc rhcostat, which in Fig. l rics with tho antenna 2Ul(l-il16 :sponsivc device 5:, and in 2 is in the local circuit; h, the wavo-rc sponsivc il'cvice, which may he of any suitable 3 t pc: 'l atelephone-receiverorothcrsuitahlc indicating or translating (.lcvicc; B, the local battery and E, the earth connection.

in the apparatus shown in Fig. 1 the variable res stance is adapted Lo be inserted in the aerial circuit hclwccn ihc antenna and the waveponsivc device in which position the acriallyq'cccived impulses HlfiiliiOnUlliXKl until thcy produce no clloct upon the wave-responsive device. In the apparatus shown in Fig. 2 the variable resistance is shown as :uhiptcil to be inserted in the local circuit, where the *csult is to render relatively insignificant the changes in the local circuit [)lOLlLlClll by the aerial impulses upon the wave-responsive (levicc. vin either case the exact amount of resistance equired to dampen clown or neutralizc this action of the :icriiil ii'npulse will he previously dctcrmincil forgiven transmittingstations and given distances zll'Hl this data he record-cv in such form thzil. it may he quickly and rcnilily referred to. This will require tho operator to do no figuring, hut simpl to sol. and read his instrument and then rclcr to his chart or table to find the distance which corresponds to the reading. the height of antenna mil length of" spnrlcgap or othcr conditions which vary the force of rzuliu'iion must be. known, it is pro nicil that this (lulu is known as to the tznnsmfiling-stal ion whose dish-inch it is l(Sli(.l Lo ostinuitc mum Irv rol crcnco to a inhlc such, for instance. as is shown at l) in tho 1 drawing the smnc l)(lll; f arranged in any zirliitrn v manner zlllll serving to inlli'zatc units of rcsisi'nncc.upon which tho il tCUllllHU'lXl1);: chart, is lw.

it is obvious that olhr-r l'orms of apparatus Elm]: iliosr shown linsr-il upon tho szmiv princlplv may hr cniplovcil. lilo not, Lhcrclorc, wish to hi:

llllllll'SLOUll as li iiing in iuvcii- IOO - pleyed to counteract the aerially-received im-- pulscs and in amounts hearing a definite ratio to the distance and power 0i astandard transmitten The combination with a receiving apparates for wireless telegraph of a range-find e1- comprising means for inserting a resistance variable in amount in series with the Waveresponsive device, and a scale indicating the amount of such resistance being used.

4. The combination with a receiving apparatus for Wireless telegraph of a rheostat and means for cutting the same into the aerial circuit between the antenna and the Wave-responsive device.

In testimony whereof I have hereunto affixeel my signature, this 10th day of June, 1903, in the presence of two Witnesses.

LEE DE FOREST.

Witnesses:

GEORGE W. THOMAS, H. E. WISE. 

